A mathematical procedure for determining the underground mining level layout which minimizes the total costs of excavation and haulage is described. This procedure has the advantage over previous graphical procedures of being easily amenable to microcomputers. The paper demonstrates through examples how the procedure can be applied to minimizing discounted costs of level layout as well as providing the optimal location of a production shaft.

A study recently completed by the Prospectors and Developers Association, assisted by the author and computerized mine models he developed, presents a strong case that present tax rules severely handicap the junior exploration company relative to the established producer. This month, Tax Notes briefly summarizes the highlights of the study and some of the Association's ideas which came out of the study.

A process of leaching niobium oxide from pyrochlore concentrate using hydrofluoric acid is described. Variables such as acid concentration, temperature, reaction time, solid/acid ratio, agitation speed and particle size are correlated to the recovery of niobium oxide.The relatively low activation energy (1,86 Kcal/mole) and the dependence of reaction rate on agitation suggest that the process is diffusion controlled. The optimum conditions for extracting niobium oxide from the leach...

La Mine Bousquet commenced operations in October 1979. Mining has been by underground methods from two main zones which dip steeply to the south. Sub-level sloping methods with following fill are used.The orebody and immediate country rocks are sericitic and highly schistose. The intensity of schistosity varies significantly and poor ground conditions prevail, especially within the orebody.Initially few mining problems were encountered but in May 1981, significant damage occurred. A system...

Major industrial restructuring, which started to manifest itself in the mature economies of the Western World and Japan in the 1970s, will accelerate in the 1980s and 1990s. Conventional heavy manufacturing industries will continue to lose ground to lighter processing/assembly operations and the new wave of high technology, information and service sectors. The decline in heavy manufacturing has severely impacted on the steel industries of Western Europe, the U.S.A. and Japan.World trade in...

In June 1983 a new borehole hoisting system was commissioned at Sherritt Gordon's Fox Mine. Twelve hundred tons-per-day of ore from the 2600 and 2800 levels are being hoisted to the 2000 level through an 8-ft diameter bored winze. This new method replaces the diesel truck haulage system which had been in operation at the mine since 1975.A study was initiated in 1980 to determine the most effective method of achieving the required production. The study examined several hoisting alternatives...